In DE 39 33 640 C2 an electrical energy supply device is disclosed for a railway train consist, wherein the energy supply device is attached so as to be able to be incorporated together with a coupling rod between two adjoining cars of the train consist, and attached via a carrier encompassing a coupling rod on the coupling rod. The energy supply device has a generator which is driven by a drive wheel running on the rail directly while inserting appropriate transmission elements.
Additional examples of generator systems for rail vehicles with friction-wheel drives are given in U.S. Pat. No. 5,828,135 and in GB 1903 0 3620.
To couple one of the named energy supply devices to a typical and customary journal box unit would involve high design expense.